Cardiovascular System


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Basic Anatomy

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Cardiovascular System

  1. 1. CIRCULATORY SYSTEM Mr. Jeremy Schriner
  2. 2. The Heart <ul><li>4 chambers </li></ul><ul><li>Located between the lungs </li></ul><ul><li>2/3 of heart left of midline </li></ul><ul><li>Apex points downward & contacts the diaphragm </li></ul><ul><li>It lies in the pericardial cavity </li></ul>
  3. 3. The Heart <ul><li>It is separated from the other organs by a double-layered membrane = Pericardium </li></ul><ul><li>The Pericardium is composed of a Fibrous Pericardium & a Serous Pericardium. The serous pericardium has 2 parts: </li></ul><ul><ul><li>1.    Parietal layer - attached to the back of the fibrous pericardium </li></ul></ul><ul><ul><li>2.    Visceral layer (epicardium) - attached to the heart muscle </li></ul></ul><ul><ul><li>These two are separated by a fluid filled space = pericardial cavity. </li></ul></ul>
  4. 4. The Heart Wall <ul><li>A. Epicardium - outermost, = Visceral layer of the serous pericardium   </li></ul>
  5. 5. Heart Wall <ul><li>  B. Myocardium - middle, = Cardiac muscle cells (very thick)     </li></ul>
  6. 6. The Heart Wall <ul><li>  C. Endocardium - innermost, forms valves, & is continuous with the endothelium of the blood vessels that enter & leave the heart </li></ul>
  7. 7. Chambers <ul><li>4 chambers </li></ul><ul><ul><li>2 upper: Lt. & Rt. Atrium </li></ul></ul><ul><ul><li>2 lower: Lt. & Rt. Ventricle </li></ul></ul>
  8. 8. Valves <ul><li>4 valves </li></ul><ul><ul><li>2 Atrioventricular (AV) Valves </li></ul></ul><ul><ul><ul><li>Rt. AV valve = tricuspid </li></ul></ul></ul><ul><ul><ul><li>Lt. AV valve = bicuspid, mitral </li></ul></ul></ul><ul><ul><li>2 semilunar valves: found at the base of 2 large vessels leaving the heart = Pulmonary & Aortic valves </li></ul></ul>
  9. 9. Blood Flow <ul><li>1. Rt. Atrium: receives deoxygenated (venous) blood from 3 vessels; </li></ul><ul><ul><li>A. Superior vena cava - blood from above the heart </li></ul></ul><ul><ul><li>B. Inferior vena cava - blood from below the heart </li></ul></ul><ul><ul><li>C. Coronary sinus - blood from the heart muscle     </li></ul></ul>
  10. 10. Blood Flow <ul><li>2. Blood flows through Rt. AV valve into Rt. Ventricle (the flaps of AV valves are held in place by Chordae Tendineae & Papillary Muscles to prevent back flow)   </li></ul>
  11. 11. Blood Flow <ul><li>3. Rt. Ventricle contracts & blood exits through the Pulmonary Semilunar valve. It enters the Pulmonary trunk which divides into Lt. & Rt. Pulmonary arteries. Blood goes to lungs (carbon dioxide out, oxygen in)   </li></ul>
  12. 12. Blood Flow cont. <ul><li>4. Oxygenated blood returns from the lungs through the Pulmonary veins to the Lt. Atrium   </li></ul><ul><li>   </li></ul>
  13. 13. Blood Flow <ul><li>  5. Blood flows through the Lt. AV valve (bicuspid, mitral) to the Lt. Ventricle   </li></ul>
  14. 14. Blood Flow <ul><li>6. Lt. Ventricle contracts & blood exits through the Aortic Semilunar valve & enters Ascending Aorta. </li></ul>
  15. 15. Coronary circulation (Blood flow to Heart Muscle) <ul><li>First vessels off of the Ascending Aorta = Lt. & Rt. Coronary Arteries </li></ul>
  16. 16. Coronary Circulation cont. <ul><li>The blood returns from the heart muscle via 2 major veins  </li></ul><ul><ul><li>1. Great Cardiac vein: brings deoxygenated blood back from the anterior heart wall  </li></ul></ul><ul><ul><li>2. Middle Cardiac vein: brings deoxygenated blood back from the posterior heart wall. </li></ul></ul><ul><li>Both vessels empty into the Coronary Sinus (a large vein on back of heart). It empties into Rt. Atrium </li></ul>
  17. 17. Conduction system <ul><li>An electrical system. It determines the rate & rhythm of the heartbeat </li></ul><ul><li>1. Sinoatrial node (SA node, pacemaker) - Neurons fire at 70/80 beats per minute, causes atria to contract   </li></ul><ul><li>2. Atrioventricular node (AV node) - neurons fire at 40-50 beats per minute; typically the SA node overrides it, but if SA node is not functioning it will ultimately cause ventricles to contract at a slower rate.   </li></ul>
  18. 18. Conduction System <ul><li>3. Atrioventricular Bundle (Bundle of His) - conducts impulses between ventricles    </li></ul><ul><li>4. The AV Bundle divides into lt & rt Bundle Branches which go to the ventricles.   </li></ul><ul><li>5. Purkinje fibers - deliver impulses directly to the myocardium of the ventricles .   </li></ul>
  19. 19. Blood – connective tissue with fluid matrix <ul><li>A. Fluid = plasma </li></ul><ul><li>B. Blood cells = formed elements </li></ul><ul><ul><li>1. Red blood cells (RBC's) = ERYTHROCYTES </li></ul></ul><ul><ul><ul><li>a. Flattened, biconcave, anucleated discs </li></ul></ul></ul><ul><ul><ul><li>b. Life span - 120 days </li></ul></ul></ul><ul><ul><ul><li>c. Function: transport oxygen & carbon dioxide bound pigmented protein = hemoglobin </li></ul></ul></ul>
  20. 20. Blood cont. <ul><li>2. White blood cells (WBC's) = LEUKOCYTES </li></ul><ul><ul><li>a.granulocytes </li></ul></ul><ul><ul><ul><li>i. eosinophils </li></ul></ul></ul><ul><ul><ul><li>ii. Basophils </li></ul></ul></ul><ul><ul><ul><li>iii. Neutrophils  </li></ul></ul></ul>
  21. 21. Blood cont. <ul><li>2. White blood cells (WBC's) = LEUKOCYTES </li></ul><ul><ul><li>b. Agranulocytes </li></ul></ul><ul><ul><ul><li>i. Monocytes </li></ul></ul></ul><ul><ul><ul><li>ii. Lymphocytes </li></ul></ul></ul>
  22. 22. Blood cont. <ul><li>3. Thrombocytes = PLATELETS; not cells. Cytoplasmic fragments of megakaryocytes. Assists in blood clot formation. </li></ul>
  23. 23. Hemopoiesis = Blood Cell formation. Occurs in red bone marrow. <ul><li>A. Erythropoiesis = RBC formation </li></ul><ul><li>B. Leukopoiesis = WBC formation </li></ul><ul><li>C. Thrombopoiesis = platelet formation </li></ul>
  24. 24. Blood vessels: blood flow <ul><li>Blood flows from the heart through progressively narrowing vessels;             artery ->arteriole -> capillary </li></ul><ul><li>And returns through progressively enlarging vessels; </li></ul><ul><li> venules -> vein-> heart   </li></ul>
  25. 25. Blood vessels <ul><li>Structure: arteries and veins have 3 tunics </li></ul><ul><ul><li>1. Tunica Externa (adventitia) - Outermost, loose connective tissue, this is the thickest layer in veins   </li></ul></ul><ul><ul><li>2. Tunica Media - middle, smooth muscle layer, this is the thickest layer in arteries   </li></ul></ul><ul><ul><li>3. Tunica Intima - innermost </li></ul></ul><ul><ul><ul><li>a. Endothelium - simple squamous + c.t. </li></ul></ul></ul><ul><ul><ul><li>b. Subendothelial layer - c.t. </li></ul></ul></ul>
  26. 26. Arteries (carry blood away from heart) <ul><li>Elastic - large amount of elastin expandable </li></ul><ul><li>Muscular - tunica media is predominantly smooth muscle. </li></ul><ul><li>There is an elastic lamina on each face of the tunica media </li></ul>
  27. 27. Arterioles - <ul><li>Smallest, tunica media very thin (<10 layers) </li></ul>
  28. 28. Capillaries <ul><li>&quot;Functional units&quot; of circulatory system, very thin-walled, allows for exchange of gases, nutrients, & waste products. </li></ul><ul><li>Composed of the Tunica Intima only </li></ul>
  29. 29. Venules   <ul><li>Usually lack a tunica media. They have the other two tunics </li></ul>
  30. 30. Veins <ul><li>Carry blood to the heart) All 3 tunics present. Veins have a very </li></ul><ul><li>Low pressure, The blood flow through them is dependent on: </li></ul><ul><ul><li>A. Contraction of surrounding musculature = Skeletal muscle &quot;pump&quot; </li></ul></ul><ul><ul><li>B. One-way valves   </li></ul></ul>